With the spread of electronic appliances including office automation apparatuses and communication instruments, electromagnetic wave emission from these appliances has come into a problem. That is, adverse effect of electromagnetic wave to the human body is feared and it is also a problem that the electromagnetic wave affects a precision apparatus to cause malfunction.
Therefore, plates having good electromagnetic-wave shielding efficiency and light transparency have developed as front filters for PDPs of the office automation apparatuses and come into commercial use. Such plates are also used as windows of a place where a precision apparatus is installed, such as a hospital or a laboratory in order to protect the precision apparatus from electromagnetic waves of a portable telephone.
A conventional electromagnetic-wave shielding and light transmitting plate typically comprises transparent base plates such as acrylic boards and a conductive mesh member like a wire netting or a transparent conductive film and is formed by interposing the conductive mesh member or the transparent conductive film between the transparent base plates and by assembling them.
In order to provide good electromagnetic-wave shielding efficiency when such an electromagnetic-wave shielding and light transmitting plate is assembled in a body of an equipment such as PDP, it is necessary to provide uniform current conduction between the electromagnetic-wave shielding and light transmitting plate and the body of the equipment, that is, between the conductive mesh of the electromagnetic-wave shielding and light transmitting plate and a conduction surface of the body.
A structure, which can provide good current conduction between an electromagnetic-wave shielding and light transmitting plate and a body of an equipment but is simple, has conventionally proposed (JPA 9-147752). This structure is made by forming a conductive mesh member in such a size that the periphery thereof is positioned outside of peripheral edges of transparent base plates so as to form margins when it is interposed therebetween, then folding the margins on the surface of one of the transparent base plates so that the margins function as conductive portions between the electromagnetic-wave shielding and light transmitting plate and the body of the equipment, and bonding the margins to the body of the equipment by pressure bonding.
However, there are the following problems with regard to such a structure as mentioned above:
1) there is a case that the conductive mesh is frayed so as not to provide good current conduction; and
2) it is difficult to fold the margins because of high toughness of the conductive mesh, and it is also difficult to bond the margins to the body of the equipment since the margins tend to be out of positions.
Therefore, the aforementioned structure has a shortcoming that it is difficult to securely provide good current conduction, which is uniform through the entire periphery of the electromagnetic-wave shielding and light transmitting plate, with low resistance.